Eosinophilic Myositis

Abstract

Eosinophilic myositis (EM) constitutes a group of rare, clinically and pathologically heterogeneous disorders characterized by eosinophil infiltration of skeletal muscle. Parasitic infection is the commonest cause worldwide, but it can also be a feature of other conditions such as hypereosinophilic syndrome or muscle dystrophies. Most cases have no known etiological factor and are considered as idiopathic. EM should be distinguished from dermatomyositis and other systemic diseases such as Churg-Strauss granulomatosis. Idiopathic EM can be classified into three subtypes: focal EM, eosinophilic polymyositis, and eosinophilic perimyositis. Pathological studies are mandatory to differentiate and diagnose these entities.